We are in the process of completing a study of the relationship between the Fowler single breath N2 washout and the surface activity of pulmonary surfactant lipoproteins obtained by bronchial-alveolar lavage from whole human lungs and upper and lower lobes. We are prepared to proceed to more direct studies on the aveoli and small airways, areas where the surfactant presumably influences lung function. We will attempt to sample the alveolar and airway surfaces directly by puncture with specially drawn glass capillaries. The lining materials, in nanoliter amounts, will be anlyzed by micro TLC and micro gel-electrophoresis and surface tension will be measured by a microbubble technique. We will also investigate the inflation of whole lungs from a degassed state when opposing surfaces either are "stuck together" (conventional degassing) or when units remain open (von Neergaard degassing). The effect of various surfactants, natural and artificial, on the opening or "ungluing" phenomena will be examined. We will measure the adhesive and wetting properties of surfactants on isolated lung tissue in order to obtain an idea of the surface forces which could exist there. Morphology of lung surfactant films lifted from a surface trough will also be examined by EM. BIBLIOGRAPHIC REFERENCES: Fine, R., Silvers, G.W., Paul, G.W., Petty, T.L., Filley, G.F.: Effect of ventilation on single breath nitrogen washouts in excised human lungs. Clin. Res. 24: 122A, 1976.